Both natural rubber and alkadiene based synthetic rubbers are useless for many purposes unless reinforced. Many different reinforcing and cross-linking agents have been developed in the art for rubbers. Sulfur curing of rubber is a technology that has been discovered very early. Using carbon black for reinforcement purposes in rubber is a very widespread technology today. A third approach to the problem of reinforcing rubber is the incorporation of mineral fillers such as silica or certain clays.
Silicas and clays are often used with organosilane additives whose function is to improve certain properties of the rubber.
The various reinforcing agents for rubber are developed with respect to specific properties of the rubber reinforced by those compositions. One of the important properties of a reinforced rubber is its hysteresis, i.e. its tendency to convert mechanical energy into heat. This property is very significant for instance for the rubber components of automotive tires. Tires are subjected to very significant mechanical working by bending and stretching. Mechanical losses result in heat build-up which may be severe enough to cause failure of the tire. Even when no such failure occurs the dissipation of energy increases fuel consumption of the vehicle on which tires are mounted.